Foldable playpen

ABSTRACT

A foldable playpen includes four top fence assemblies, four side fence assemblies and a bottom frame assembly, the first end of each bottom frame rail being movably attached to the bottom frame foldable connector; an operating device for engaging the four top fence joint assemblies with the bottom frame foldable connector; four operating ropes, each operating rope having a first end and a second end, for enabling the top fence rails and the bottom frame rails to respond to a movement of the bottom frame foldable connector so as to switch the foldable playpen to a folded state from an open state, the first end of an operating rope is connected to a top fence joint assembly, and the second end of an operating rope is connected to the bottom frame foldable connector. The playpen can synchronously fold the bottom frame rails and the top fence rails, and is safe and reliable.

RELATE APPLICATIONS

This application is a national phase entrance of and claims benefit to PCT Application for a foldable playpen, PCT/CN2015/088322, filed on Aug. 28, 2015, which claims benefit to Chinese Patent Applications 201410520146.9, filed on Sep. 30, 2014. The specifications of both applications are incorporated here by this reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of playpens and in particular to a foldable playpen.

BACKGROUND OF THE INVENTION

A baby playpen, as a safe place for babies to sleep and play, can be used both at home and on a trip. The playpen can also create a safe area for babies, especially when they can crawl or when they become passionately curious. As babies grew up with increased activities, the playpen can also be a safe place for babies if you must do something else, such as work or homework. In order to occupy less space and be convenient to move, the playpen is usually convenient to be folded. A foldable playpen in the prior art includes four top fence rails, four columns, and feet provided at lower ends of the four columns; and rollers are usually provided at lower ends of the feet. When folded, the four top fence rails and base frames are respectively bent or pivoted by a joint structure to draw all of the top fence rails, four side walls and the base frames close to each other, so that the volume of the playpen is reduced. However, the problem is that a base frame folding-unfolding device in the prior art is complex in structure, and the joint structures of the base frame folding-unfolding device and the four top fence rails cannot be synchronously folded so that the folding-unfolding operations are troublesome. Therefore, a foldable playpen has appeared on the market, and this playpen device can be unfolded when in use and folded for transportation or storage quickly and easily. A central assembly is positioned in the center, and lower assemblies and upper assemblies are connected by cables. However, the problem is that, in order to unfold or fold the upper assemblies by the cables in response to the up-and-down linear movement of the central assembly, the groups of cables are coordinated with cam followers which are mounted on lower legs on upper portions pivotally connected to lower corner assemblies. That is, the cables are extended upward by side bars pivotally connected to a same lower corner assembly, and then divided into two strands to be conveniently connected to ends of two adjacent upper arms. It is very difficult and time-consuming to thread and mount the cables. Moreover, due to the complex threading of cables, jamming occurs easily. And, due to the complex threading of cables, the yield of qualified products is decreased, resulting in increased manufacturing cost.

SUMMARY OF THE INVENTION

A technical problem to be solved by the present invention is to provide a foldable playpen which is convenient for mounting, low in cost and convenient in operation, can synchronously fold bottom frame rails and top fence rails, and is safe and reliable.

A technical solution employed by the present invention to solve the technical problem is as follows: a foldable playpen is provided, comprising a bottom frame assembly with a bottom frame foldable connector, four bottom frame rails, each bottom frame rail having a first end and a second end, the first end of each bottom frame rail being movably attached to the bottom frame foldable connector, the second end of each bottom frame rail being attached to a foot support; four top fence assemblies, each top fence assembly having a first top fence rail, a second top fence rail and a top fence joint assembly; four side fence assemblies, each side fence assembly having a side fence; and four vertical supports, each vertical support having an upper end and a lower end, the upper end of each vertical support being connected to the first top fence rail of a top fence assembly and the second top fence rail of an adjacent top fence assembly, the lower end of each vertical support being connected to a foot support; an operating device for engaging the four top fence joint assemblies with the bottom frame foldable connector; four operating ropes, each operating rope having a first end and a second end, for enabling the top fence rails and the bottom frame rails to respond to a movement of the bottom frame foldable connector so as to switch the foldable playpen to a folded state from an open state, wherein the first end of an operating rope is connected to a top fence joint assembly, and the second end of an operating rope is connected to the bottom frame foldable connector.

Compared with the prior art, the present invention has the following advantages: the operating device of the foldable playpen comprises four operating ropes used for enabling the top fence rails and the bottom frame rails to respond to the movement of the bottom frame foldable connector so as to switch the playpen to a folded state from an unfolded state; and the first end of an operating rope is connected to a top fence joint assembly, and the second end of an operating rope is connected to the bottom frame foldable connector. In actual mounting, the operating ropes are arranged along the side fence of the playpen, and one end of each operating rope is connected to the corresponding top fence joint assembly and the other end thereof is connected to the bottom frame foldable connector. The playpen is simple in structure and very convenient for mounting, can synchronously fold the bottom frame rails and the top fence rails, and is safe and reliable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a foldable playpen according to an Embodiment 1 of the present invention;

FIG. 2 is a perspective view of the playpen according to the Embodiment 1 of the present invention, in which a half of bottom frame rails and the bottom frame foldable connector are removed;

FIG. 3 is an enlarged perspective view of the bottom frame foldable connector at part A of FIG. 2;

FIG. 4 is a perspective view of the bottom frame foldable connector according to the Embodiment 1 of the present invention, when an upper base is in an exploded state;

FIG. 5 is a perspective view of the bottom frame foldable connector in a foldable process according to the Embodiment 1 of the present invention;

FIG. 6 is a perspective view of a top fence assembly according to the Embodiment 1 of the present invention, when a connecting base is in an exploded state;

FIG. 7 is a perspective view of the top fence assembly in a folding process according to the Embodiment 1 of the present invention;

FIG. 8 is a perspective view of a top fence assembly according to an Embodiment 2 of the present invention, when a connecting base is in an exploded state;

FIG. 9 is a perspective view of the top fence assembly in a folding process according to the Embodiment 2 of the present invention;

FIG. 10 is a perspective view of a top fence assembly according to an Embodiment 3 of the present invention, when a connecting base is in an exploded state;

FIG. 11 is a perspective view of a bottom frame foldable connector according to the Embodiment 2 of the present invention, when a mounting base is open; and

FIG. 12 is a perspective view of the bottom frame foldable connector in a folding process according to the Embodiment 2 of the present invention.

The reference numbers and the corresponding component names in FIG. 1-5 are listed as follows: 1-bottom frame rail; 2-mounting base; 2.1-outer base; 2.1.1-neck; 2.2-inner base; 2.3-upper base; 2.4-connecting base; 2.4.1-slotted hole; 3-operating rope; 3.1-cord; 3.2-jacket; 4-first unlocking member; 4.1-guide groove; 5-first pin; 6-second unlocking member; 6.1-oscillating arm; 7-guide post; 8-second pin; 9-roller; 10-oscillating member; 11-third pin; 12-second torsional spring; 13-unlocking rope; 14-connecting member; 15-enclosure; 15.1-handle; 16-auxiliary bottom frame rail; 17-fixed column; 18-mounting shaft; 19-bottom frame foldable connector.

The reference numbers and the corresponding component names in FIG. 6-7 are listed as follows: 3-operating rope; 3.1-cord; 3.2-jacket; 20-top fence joint assembly; 21-first top fence rail; 22-second top fence rail; 22.1-second arc-shaped groove; 23-connecting base; 23.1-sliding groove; 24-pedestal; 25-first crank; 26-second crank; 27-restoring spring; 28-first rotating shaft; 29-second rotating shaft; 30-guide pin; 31-connecting rod; 32-first pin; 33-first roller; 34-second pin; 35-second roller.

The reference numbers and the corresponding component names in FIG. 8-9 are listed as follows: 3-operating rope; 3.1-cord; 3.2-jacket; 210-first top fence rail; 220-second top fence rail; 220.1-second arc-shaped groove; 230-connecting base; 230.1-sliding groove; 240-fixed pin; 250-crank; 260-oscillating rod; 260.1-extended section; 270-torsional spring; 280-first rotating shaft; 29-0second rotating shaft; 300-guide pin; 310-limiting seat; 320-first pin; 330-first roller; 340-second pin; 350-second roller.

The reference numbers and the corresponding component names in FIG. 10 are listed as follows: 3-operating rope; 3.1-cord; 3.2-jacket; 021-first top fence rail; 022-second top fence rail; 023-connecting base; 023.1-first sliding groove; 023.2-second sliding groove; 023.4-third sliding groove; 024-guide element; 024.1-first guide groove; 024.2-second guide groove; 025-first pin; 026-second pin; 027-guide pin; 028-pedestal; 029-torsional spring.

The reference numbers and the corresponding component names in FIG. 11-12 are listed as follows: 01-bottom frame rail; 02-mounting base; 3-operating rope; 3.1-cord; 3.2-jacket; 04-roller; 04.1-rotating shaft; 05-sliding base; 06-handle.

DETAILED DESCRIPTION OF THE INVENTION

To enable a further understanding of the present invention content of the invention herein, refer to the detailed description of the invention and the accompanying drawings below:

As shown in FIG. 1, a foldable playpen is provided, comprising a bottom frame assembly with a bottom frame foldable connector 19, four bottom frame rails 1, each bottom frame rail having a first end and a second end, the first end of each bottom frame rail being movably attached to the bottom frame foldable connector, the second end of each bottom frame rail being attached to a foot support; four top fence assemblies, each top fence assembly having a first top fence rail 21, a second top fence rail 22 and a top fence joint assembly 20; four side fence assemblies, each side fence assembly having a side fence; and four vertical supports, each vertical support having an upper end and a lower end, the upper end of each vertical support being connected to the first top fence rail of a top fence assembly and the second top fence rail of an adjacent top fence assembly, the lower end of each vertical support being connected to a foot support; an operating device for engaging the four top fence joint assemblies 20 with the bottom frame foldable connector 19; four operating ropes 3, each operating rope having a first end and a second end, for enabling the top fence rails 21,22 and the bottom frame rails 1 to respond to a movement of the bottom frame foldable connector 19 so as to switch the foldable playpen to a folded state from an open state, wherein the first end of an operating rope 3 is connected to a top fence joint assembly 20, and the second end of an operating rope 3 is connected to the bottom frame foldable connector 19.

As shown in FIG. 1 and FIG. 2, in this embodiment, the playpen further comprises a fabric cover covering four side fence assemblies, the fabric cover has four threading passages for four operating rope 3 to pass through.

In this embodiment, as shown in FIGS. 2-5, the bottom frame foldable connector 19 comprises a mounting base 2 and four unlocking devices, the mounting base 2 has an outer base 2.1 having a chamber, an outer wall, an inner wall, and an inner base 2.2 slidably disposed in the chamber, the four bottom frame rails 1 are hinged to the outer base 2.1, the first ends of the bottom frame rails 1 are pivotally connected with the inner base 2.2 by a connecting member 14;

each unlocking device has a first unlocking member 4 with an upper end and a lower end and a second unlocking member 6 for activating the first unlocking member 4; the first unlocking member 4 is rotatably connected to the outer base 2.1 by a first pin 5, and the second end of each operating rope 3 is fixedly connected to the upper end of the first unlocking member 4; a middle portion of the second unlocking member 6 is rotatably connected to the inner base 2.2 by a second pin 8, a first torsional spring for restoring is sleeved outside the second pin 8; an oscillating arm 6.1, used for driving the lower end of the first unlocking member 4 to act in a folding-unfolding process so as to cause the first unlocking member 4 to rotate around the first pin 5 and to drive the operating rope 3 to act, is provided at one end of the second unlocking member 6; each operating rope 3 further comprises a cord 3.1 disposed inside a jacket 3.2, and an end of the cord 3.1 is connected to the upper end of the first unlocking member 4 and an end of the jacket 3.2 rests against the outer wall of the outer base 2.1. The operating rope used in the present invention, having a structure similar to that of a brake cable used in bicycles, motorcycles and the like, is a common product available in the market and also called control cable. The operating rope can be purchased by those skilled in the art and will not be repeatedly described here.

The playpen further comprises an unlocking protection device with an oscillating member 10 disposed in the chamber and rotatable connected to the bottom of the inner base 2.2 through a third pin 11, and a neck 2.1.1 for clamping one end of the oscillating member 10 is provided on the inner wall of the outer base 2.1, and a second torsional spring 12 for restoring is disposed out of the third pin 11. The unlocking protection device further comprises an upper base 2.3, a connecting base 2.4 mounted between the upper base 2.3 and the inner base 2.2, and an unlocking rope 13 with an upper end and a lower end; a lower end of the connecting base 2.4 is connected to the inner base 2.2; a slotted hole 2.4.1 is defined on the connecting base 2.4 in an axial direction, and the upper base 2.3 passes through the slotted hole 2.4.1 from a mounting shaft 18 and is connected to the inner base 2.2; the upper end of the unlocking rope 13 is fixed on the mounting shaft 18 and the lower end thereof is fixed on the oscillating member 10. In this way, by setting this unlocking protection device, accidental operations caused when cats, dogs and other small animals enter the bottom of the playpen can be effectively prevented, and the playpen is thus safer and more reliable.

A roller 9, used for coordinating with the oscillating arm 6.1 of the second unlocking member 6, is rotationally mounted at the lower end of the first unlocking member 4. In this way, the friction can be effectively reduced, so that the folding or unfolding operation becomes smoother.

An arc-shaped guide groove 4.1 is provided on the first unlocking member 4; and a guide post 7 is in sliding fit in the arc-shaped guide groove 4.1, and the guide post 7 is fixedly mounted on the inner wall of the outer base 2.1. In this way, the rotation of the first unlocking member 4 can be guided and limited, so that the playpen is safer and more reliable.

An enclosure 15, having a middle portion sleeved on a peripheral surface of the upper base 2.3, is provided on an upper surface of the outer base 2.1; a handle 15.1, which is used for mounting a carrying strap and exposed to the enclosure 15, is transversely provided on the enclosure 15. In this way, the unlocking device and the unlocking protection device inside the mount can be better protected, so that the playpen is safer and more reliable.

A fixed column 17 is fixedly mounted on the inner base 2.2 at a position near the second unlocking member 6, and one end of the first torsional spring is resisted against an inner wall of the second unlocking member 6 and the other end thereof is resisted against the fixed column 17. In this way, the second torsional spring can be effectively fixed and the elastic restoring effect of the second unlocking member is better.

One end of the connecting member 14 is hinged to the ends of the bottom frame rails 1 and the other end thereof is hinged to the inner base 2.2.

Four auxiliary bottom frame rails 16 are provided in parallel on lower portions of the four bottom frame rails 1, and one end of each auxiliary bottom frame rail 16 is hinged to the outer base 2.1 and the other end thereof is hinged to the feet of the playpen. In this way, when folded, the bottom frame rails have better synchronization and can play a certain role of buffering, so that the foldable effect is better.

When the playpen is required to be folded, the carrying strap mounted on the handle 15.1 is pulled upward in order to drive the upper base 2.3 to move upward, and the unlocking rope on the mounting shaft 18 drives the oscillating member 10 to separate from the neck 2.1.1 of the outer base 2.1, i.e., drives the inner base 2.2 to slide upward along the chamber of the outer base 2.1; after the upper base 2.3 moving upward for a certain distance, i.e., the length of the slotted hole 2.4.1 on the connecting base 2.4, and the inner base 2.2 continues to move upward until the oscillating arm 6.1 of the second unlocking member 6 drives the roller 9 at the lower end of the first unlocking member 4 to act to enable the first unlocking member 4 to rotate around the first pin 5 and to drive the operating rope 3 to act.

As shown in FIG. 6 and FIG. 7, the playpen further comprises a connecting base 23 for rotatably connecting the first top fence rail 21 and the second top fence rail 22 of each top fence assembly; a fence joint assembly, for the first top fence rail 21 and the second top fence rail 22 to change from a vertically folded state to a horizontal state, is connected between the first top fence rail 21 and the second top fence rail 22; the fence joint assembly comprises a first crank 25 with two ends and a middle portion, a second crank 26 with two ends and a middle portion, and a restoring spring 27 with an upper end and a lower end sleeved on the periphery of the operating rope 3; a first end of the first crank 25 rests against the first top fence rail 21 and the middle portion thereof is rotationally connected to the connecting base 23 by a first rotating shaft 28; a first end of the second crank 26 rests against the second top fence rail 22 and the middle portion thereof is rotationally connected to the connecting base 23 by a second rotating shaft 29; a second end of the first crank 25 is hinged to a second end of the second crank 26 by a guide pin 30; each operating rope 3 is fixedly connected to the guide pin 30 and used for driving the guide pin 30 to slide in vertical direction; each operating rope 3 comprises a cord 3.1 disposed inside a jacket 3.2, an end of the cord 3.1 is fixedly connected to the guide pin 30, and an end of the jacket 3.2 is resisted against a bottom wall of a pedestal 24 on the bottom of the connecting base 23.

A sliding groove 23.1, used for guiding the guide pin 30 which is in sliding fit in the sliding groove 23.1 to slide therein, is vertically provided on the connecting base 23.

The pedestal 24, against which the lower end of the restoring spring 27 is resisted, is provided on the bottom of the connecting base 23.

A vertically-arranged connecting rod 31, having a hollow through cavity, is fixedly mounted on the guide pin 30; a spring 37 is sleeved on the periphery of the connecting rod 31, with an upper end of the spring 37 being rested against the connecting rod 31 and a lower end of the spring 37 being rested against the upper end of the pedestal 24.

A first pin 32, on which a first roller 33 is sleeved, is sleeved at one end of the first crank 25, and a first arc-shaped groove 21.1 resisted against the first roller 33 is disposed at an end of the first top fence rail 21; a second pin 34, on which a second roller 35 is sleeved, is sleeved at one end of the second crank 26, and a second arc-shaped groove 22.1 resisted against the second roller 35 is disposed at an end of the second top fence rail 22.

The joint assemblies are symmetrically arranged around the axis of the operating rope 3.

When the bottom frame foldable connector tows the operating rope 3 to act, the upper end of the operating rope 3 drives the guide pin 30 to slide downward along the sliding groove 23.1 on the connecting base 23, and drives the first crank 25 and the second crank 26 to respectively rotate around the first rotating shaft 28 and the second rotating shaft 29, so that the upper ends of the first crank 25 and the second crank 26 are warped upward. The first crank 25 and the second crank 26 are respectively separated from the first top fence rail 21 and the second top fence rail 22. The friction between the first crank 25 and the first top fence rail 21 and between the second crank 26 and the second top fence rail 22 can be reduced effectively through the coordination of the roller and the arc-shaped groove, so that the separation becomes smoother. The first top fence rail 21 and the second top fence rail 22 can be folded by rotating around the connecting base 23. In this way, the synchronous folding or unfolding of the bottom frame rails and the top fence rails can be achieved. The operation is very easy.

FIG. 8 and FIG. 9 show Embodiment 2 of the top fence assemblies according to the present invention. The playpen further comprises a connecting base 230 for rotatably connecting a first top fence rail 210 and a second top fence rail 220 of each top fence assembly; a fence joint assembly, for the first top fence rail 210 and the second top fence rail 220 to change from a vertically folded state to a horizontal state, is connected between the first top fence rail 210 and the second top fence rail 220; the fence joint assembly comprises a crank 250 and with two ends and a middle portion, an oscillating rod 260 with two ends and a middle portion, and a restoring spring 270 with an upper end and a lower end; a first end of the crank 250 rests against the first top fence rail 210 and the middle portion thereof is rotationally connected to the connecting base 230 by a first rotating shaft 280; a first end of the second crank 260 rests against the second top fence rail 220 and the middle portion thereof is rotationally connected to the connecting base 230 by a second rotating shaft 290, on which an extended section 260.1 is provided; a second end of the crank 250 is hinged to extended section 260.1 by a guide pin 300. A operating rope 3, which is used for towing a lower portion of a oscillating rod 260 to act and has the other end connected to a bottom frame foldable connector of the playpen, is connected to the lower portion of the oscillating rod 260. One end of a torsional spring 270 is fixed on the connecting base 230 and the other end thereof is fixed at a lower end of the oscillating rod 260 by a fixed pin 240. Each operating rope 3 comprises a cord 3.1 disposed inside a jacket 3.2, an end of the cord 3.1 is fixedly connected to the oscillating rod 260, and the cord 3.1 is roughly horizontal. A limiting seat 310, in which a mounting hole used for receiving the jacket 3.2 is formed, is provided on the bottom of the connecting base 230, and an end of the jacket 3.2 is resisted against an inner wall of the mounting hole. As shown in FIG. 8 and FIG. 9, the operating rope 3 is roughly horizontal, in this way, the threading paths inside the side fence sleeve of the playpen can also be arranged transversely and then gathered downward to the base frame. Accordingly, the influence on the appearance of the side fence sleeve of the playpen can be effectively avoided.

A sliding groove 230.1, used for guiding a guide pin 300 which is in sliding fit in a sliding groove 230.1 to slide, is vertically provided on the connecting base 230.

A first pin 320, on which a first roller 330 is sleeved, is sleeved at one end of the crank 250, and a first arc-shaped groove 210.1 resisted against the first roller 330 is disposed at an end of the first top fence rail 210; a second pin 340, on which a second roller 350 is sleeved, is sleeved at one end of the oscillating rod 260, and a second arc-shaped groove 220.1 resisted against the second roller 350 is disposed at an end of the second top fence rail 220.

FIG. 10 shows Embodiment 3 of the top fence assemblies according to the present invention. The playpen further comprises a connecting base 023 for rotatably connecting a first top fence rail 021 and a second top fence rail 022 of each top fence assembly; a first sliding groove 023.1, and a second sliding groove 023.2 and a third sliding groove 023.3 which are symmetrically and diagonally arranged, are respectively provided on the connecting base 023. A guide element 024, on which a first guide groove 024.1 and a second guide groove 0.24.2 are provided, is in sliding connection with the connecting base 023 after passing through the first sliding groove 023.1 from a guide pin 027. A lower end of a torsional spring 029 is fixed on the guide pin 027 and an upper end thereof is fixed on the connecting base 023. A first pin 025 and a second pin 026 are symmetrically provided on two sides of the guide pin 027; the first pin 025 is in sliding fit in the first guide groove 024.1 and the second sliding groove 023.2, and the second pin 026 is in sliding fit in the second guide groove 024.2 and the third sliding groove 023.3; and the first pin 025 is resisted against a lower end of an end portion of the first top fence rail 021, and the second pin 026 is resisted against a lower end of an end portion of the first top fence rail 022. Each operating rope 3 is fixedly connected to the guide pin 027 and used for driving the guide pin 027 to slide in vertical direction; each operating rope 3 comprises a cord 3.1 disposed inside a jacket 3.2, an end of the cord 3.1 is fixedly connected to the guide pin 027, and an end of the jacket 3.2 is resisted against a bottom wall of a pedestal 028 on the bottom of the connecting base 23.

FIG. 11 and FIG. 12 show Embodiment 2 of another structure of the bottom frame foldable connector according to present invention. The bottom frame foldable connector 19 comprises a mounting base 02 provided at an intersection of the four bottom frame rails 01, and the four bottom frame rails 1 are hinged to the mounting base 02 near their ends. The mounting base 02 has a chamber. A roller 04 is rotationally connected to the inside of the mounting base 02 by rotating shafts 04.1 which are transversely arranged at the two ends. Each operating rope 3 further comprises a cord 3.1 disposed inside a jacket 3.2, and a sliding base 05 is in sliding fit with the chamber of the mounting base 02. A handle 06 used for mounting a carrying strap is provided at an upper end of the sliding base 05. The ropes are all wound around the roller 04 and then fixedly connected to the sliding base 05, and an end of the jacket is resisted against an outer wall of the mounting base 02.

The protection scope of the present invention is not limited to each embodiments described in this description. Any changes and replacements made on the basis of the scope of the present invention patent and of the description shall be included in the scope of the present invention patent. 

1. A foldable playpen comprising: a bottom frame assembly with a bottom frame foldable connector, four bottom frame rails, each bottom frame rail having a first end and a second end, the first end of each bottom frame rail being movably attached to the bottom frame foldable connector, the second end of each bottom frame rail being attached to a foot support; four top fence assemblies, each top fence assembly having a first top fence rail, a second top fence rail and a top fence joint assembly; four side fence assemblies, each side fence assembly having a side fence; and four vertical supports, each vertical support having an upper end and a lower end, the upper end of each vertical support being connected to the first top fence rail of a top fence assembly and the second top fence rail of an adjacent top fence assembly, the lower end of each vertical support being connected to a foot support; an operating device for engaging the four top fence joint assemblies with the bottom frame foldable connector; four operating ropes, each operating rope having a first end and a second end, for enabling the top fence rails and the bottom frame rails to respond to a movement of the bottom frame foldable connector so as to switch the foldable playpen to a folded state from an open state, wherein the first end of an operating rope is connected to a top fence joint assembly, and the second end of an operating rope is connected to the bottom frame foldable connector.
 2. The playpen of claim 1, further comprising a fabric cover covering four side fence assemblies, the fabric cover has four threading passages for four operating rope to pass through.
 3. The playpen of claim 2, wherein the bottom frame foldable connector further comprises a mounting base and four unlocking devices, the mounting base has an outer base having a chamber, an outer wall, an inner wall, and an inner base slidably disposed in the chamber, the four bottom frame rails are hinged to the outer base, the first ends of the bottom frame rails are pivotally connected with the inner base by a connecting member; each unlocking device has a first unlocking member with an upper end and a lower end and a second unlocking member for activating the first unlocking member; the first unlocking member is rotatably connected to the outer base by a first pin, and the second end of each operating rope is fixedly connected to the upper end of the first unlocking member; a middle portion of the second unlocking member is rotatably connected to the inner base by a second pin, a first torsional spring for restoring is sleeved outside the second pin; an oscillating arm, used for driving the lower end of the first unlocking member to act in a folding-unfolding process so as to cause the first unlocking member to rotate around the first pin and to drive the operating rope to act, is provided at one end of the second unlocking member; each operating rope further comprises a cord disposed inside a jacket, and an end of the cord is connected to the upper end of the first unlocking member and an end of the jacket rests against the outer wall of the outer base.
 4. The playpen of claim 3, wherein the playpen further comprises an unlocking protection device with an oscillating member disposed in the chamber and rotatable connected to the bottom of the inner base through a third pin, and a neck for clamping one end of the oscillating member is provided on the inner wall of the outer base, and a second torsional spring for restoring is disposed out of the third pin.
 5. The playpen of claim 4, wherein the unlocking protection device further comprises an upper base, a connecting base mounted between the upper base and the inner base, and an unlocking rope with an upper end and a lower end; a lower end of the connecting base is connected to the inner base; a slotted hole is defined on the connecting base in an axial direction, and the upper base passes through the slotted hole from a mounting shaft and is connected to the inner base; the upper end of the unlocking rope is fixed on the mounting shaft and the lower end thereof is fixed on the oscillating member.
 6. The playpen of claim 1, further comprising a connecting base for rotatably connecting the first top fence rail and the second top fence rail of each top fence assembly; a fence joint assembly, for the first top fence rail and the second top fence rail to change from a vertically folded state to a horizontal state, is connected between the first top fence rail and the second top fence rail; the fence joint assembly comprises a first crank with two ends and a middle portion, a second crank with two ends and a middle portion, and a restoring spring with an upper end and a lower end sleeved on the periphery of the operating rope; a first end of the first crank rests against the first top fence rail and the middle portion thereof is rotationally connected to the connecting base by a first rotating shaft; a first end of the second crank rests against the second top fence rail and the middle portion thereof is rotationally connected to the connecting base by a second rotating shaft; a second end of the first crank is hinged to a second end of the second crank by a guide pin; each operating rope is fixedly connected to the guide pin and used for driving the guide pin to slide in vertical direction; each operating rope comprises a cord disposed inside a jacket, an end of the cord is fixedly connected to the guide pin, and an end of the jacket is resisted against a bottom wall of a pedestal on the bottom of the connecting base.
 7. The playpen of claim 6, wherein a vertically-arranged connecting rod, having a hollow through cavity, is fixedly mounted on the guide pin; a spring is sleeved on the periphery of the connecting rod, with an upper end of the spring being rested against the connecting rod and a lower end of the spring being rested against the upper end of the pedestal.
 8. The playpen of claim 6, wherein a fourth pin, on which a first roller is sleeved, is sleeved at one end of the first crank, and a first arc-shaped groove resisted against the first roller is disposed at an end of the first top fence rail; a fifth pin, on which a second roller is sleeved, is sleeved at one end of the second crank, and a second arc-shaped groove resisted against the second roller is disposed at an end of the second top fence rail.
 9. The playpen of anyone of claim 1 and claim 3, wherein four auxiliary bottom frame rails are provided in parallel on lower portions of the four bottom frame rails, and one end of each auxiliary bottom frame rail is hinged to the outer base and the other end thereof is hinged to the feet of the playpen. 